THE SOFT light of a lime green sunset appeared to cover Mogadishu as a US 'Blackhawk' helicopter raced in darkness above the tin-roofed buildings of the sprawling Bakaraha market, where the fugitive warlord General Mohamed Farah Aideed was believed to be hiding.

The pilots, machine-gunners and passengers wore night vision goggles, worth dollars 14,000 (pounds 9,500) each, which produced the eery green light and allowed the helicopter to see everything below. A specially-designed reconnaissance aircraft, at night the Blackhawk is virtually invisible from the ground.

The Blackhawk suddenly privoted 180 degrees, its attention caught by the sight of a pick-up truck moving slowly near the ruins of Gen Aideed's headquarters, which were destroyed last week by US AC-130 gunships serving with the UN intervention force in Somalia. There it hovered for several minutes till it was satisfied that nothing was amiss.

As the search for Gen Aideed, wanted for allegedly ordering the 5 June massacre of 24 Pakistani soldiers, entered its second week, the UN operation in Somalia (Unosom) began distributing Wild West-style wanted posters offering a reward. But Unosom's diligence has been called into question by the interviews granted to journalists by the faction leader.

Gen Aideed has professed innocence in the killings and accused the United Nations of killing hundreds of civilians in its campaign against militiamen of his United Somali Congress (USC). He has vowed not to leave Mogadishu.

The UN has detained 56 Somalis, including two pro-Aideed police generals, for an indefinite period under broad powers of 'administrative detention' that are routinely used in emergency situations by military dictatorships. A UN spokesman explained that because Unosom had 'reasonable grounds' to believe the detainees were a threat to public order, they could be held for 45 to 60 days.

Behind the scenes, the UN special envoy to Somalia, retired US navy Admiral Jonathan Howe, has been negotiating with Gen Aideed's military allies in the Somali National Alliance (SNA) and elders of his Habir Gedir clan to persuade them to abandon him.

He appeared to score an important victory on Wednesday when, according to UN spokesmen, Abdi Warsame, leader of the Southern Somali National Movement, one of four armed factions in the SNA, said he was no longer committed to alliance with the general.

Ali Mahdi Mohamed, who engaged General Aideed in a four- month civil war in late 1991 and early 1992 that destroyed much of central Mogadishu, said this week that leaders of four of the sub-clans which make up the Habir Gedir had defected, with only Gen Aideed's Saad sub-clan remaining loyal.